The present invention relates to positioning systems for positioning a movable body with respect to a reference path. The invention is particularly useful for positioning agricultural implements with respect to one or more rows of crops, and is therefore described below with respect to this application.
Efforts are continuously being made to streamline the production of row crops, in order to reduce the operating expenses and also to increase the yields. Both operating expenses and crop yields are substantially affected by the proximity at which agricultural implements can approach the plant rows, without causing damage, during various farming operations, such as uprooting of weeds from the vicinity of plants, spraying the plants, and fertilizing the ground. For these reasons, various precision farming tools have been developed for use during sowing of seeds which permit more efficient cultivation and which reduce considerably the operating expenses. However, the agricultural equipment now available usually can operate no closer than about 10 cm from the plant on level ground without danger of damaging the plants.
As a partial solution to this problem, some agricultural implements include independent guidance systems which are guided by an additional worker in addition to the tractor driver. However, such guidance systems not only require an extra worker, but also are subject to human judgement and control, and therefore require significant response times and are limited as to the closeness to which the agricultural implement can approach the plant crops without danger of damaging them.